The utilization of drums of all kinds is well known, whether it is a question of storing, or transporting solid or liquid products.
In all cases, and regardless of the dimensions of the different models, the drum is composed of a body which is generally cylindrical and often fluted, a bottom which is often convex and a top that is generally flat.
These different parts are assembled in such a way that the drum may be, in principle, hermetically sealed, the openings usually being located on the upper flat plate, in the form of, for example, two screw bungs with a threaded plug.
However, the part called the "upper flat" is in fact assembled in a recess with respect to the cylindrical walls of the drum, and thus constitutes a sort of upper tray, or depression, more or less deep, depending on the types of drums.
The drums are often made of metal and are used to store products such as lubricants. When the drums are stored outside, or are temporarily exposed to bad weather, or even during transport, thus upper tray, or depression, constitutes a reservoir for rainwater. Without any device for keeping it from so collecting, the water may, after a period of time, penetrate and infiltrate the metallic drum, with the risk of alterating the quality of the products, the lubricants for example, which are therein stored.
There is thus a technical risk for the manufacturer who stores and delivers his products in metallic drums of having to face complaints from his customers in the event such alteration by infiltration occurs, or that it might have occurred at any moment whatsoever before the drums containing the products were delivered to the customers.